Water armed fuze



pril 29, 1947. G, E, BREEZE ETAL 2,419,815

WATER ARMED FUZE F`i1ed Oct. 3, 1944 R/ mn i RAW MIS Kw v I l n @t Q vut R n mvENToRs GEORGE E. BREEZE 600W/N I?. E GAY ATTORNEY Patented Apr. 29, 1947 F Fl E WATER ARMED FUzE George E. Breeze, Uncasville, Conn., and Godwin R. F. Gay, Garden City, N. Y.; said Breeze assignor of his right to the ment, as represented by Navy United States Governthe Secretary of the Application October 3, 1944, Serial No. 556,952 7 Claims. (Cl. 10ft-17)' This invention relates to a iuze for detonating an explosive charge and is particularly directed to a contact type fuze adapted to be placed in a projectile for use beneath the surface of a body of water.

The general object of the invention is to provide a fuze which is safe to handle but which may be armed at the desired time by the action of the water in which it is submerged so that it is in position to detonate the explosive charge, without fail, at the time of contact with the target.

A further object of the invention is to provide a fuze in which increased safety in handling prior to arming is obtained by spacing the detonator from the booster, using a normally inactive source of electrical energy to fire the detonator and interposing a normally open switch between the detonator and current source.

1n its preferred form, the fuze comprises a cylindrical tube in one end of which is located a booster charge. The booster charge is provided with a centrally recessed portion into which a detonator is moved when the fuze is armed for use. Arming of the fuze requires not only moving the detonator into the booster charge, but also establishing a source of electric energy to ignite the booster upon contact with the target and closing a switch interposed between the detonator and the source of energy. A second switch is provided which is closed at the time contact is made with a target to complete the circuit and explode the detonator, booster and main charge in succession.

For a better understanding of the invention, reference may be had to the accompanying drawing, in which Fig. 1 is a side elevation oi a projectile having one form of the new fuze, part of the projectile being broken away to show the fuze;

Fig. 2 is an enlarged longitudinal sectional view of the fuZe;

Fig. 3 is a detail view of a switch used in the electrical circuit of the fuze;

Fig. 4 is a wiring diagram showing the electric circuit, and

Fig. 5 is a sectional view on the line 5-5 in` Fig. 2. f

Referring now to Fig. 1, it will be seen that the fuze 6 is mounted in the nose portion of the projectile 8 and that its axis coincides with that of the projectile. The fuze is surrounded by e explosive charge (not shown) which is detonaf ed by the fuze through the usual booster at thevtime a target is contacted. q

The fuze as shown in Fig. 2 compiises a housing is a part of the subassembly.

in the form of a hollow tube IIJ made of brass or other suitable material. Near its Arear end, the tube is swaged inwardly at I2 to retain a booster charge I4 in place against an internal flange I3 on the rear end of the tube, the booster having a central recess I5 in its iront end. The tube is open at its nose end to receive a cap I5a. which is tightly wedged and secured in the tube with a shoulder I6 of the cap in abutment with the tube end. The cap has an external thread I1 which is adapted to be screwed into a corresponding internal thread in the nose of the projectile to secure the iuze mechanism in place.

A subassembly generally indicated at 20 is slidably mounted in the tube I0 and comprises a resin impregnated ber piston 2| formed at each end with an external annular flange 22. Adjacent the rear iiange 22 is a rubber packing ring 23 held in an annular recess in the piston 2|. A brass sleeve 25 is snugly secured over a hollow boss 2 la forming the rear end portion of the piston 2| and The sleeve is swaged inwardly at its rear end which carries an electrically-red detonator 21 adapted to t into the booster recess I5 but normally disposed a substantial distance in front of the booster.

To fire the detonator at the desired time, a source of electric current is provided which is inactive until water, preferably sea water because of the salts therein, comes into contact' with its component parts. The current source is a wateractivated sea cell which is indicated at 30 in Fig. 2 and is shown schematically in Fig. 4.

The circuit between the cell 3|) and the detonator 21 is normally open but is partially closed at the time the fuze is armed and is completely closed at the time of firing. To this end, a normally open switch 35 is connected in series with the detonator and the cell 30, the switch comprising a hollow supporting ring 36 formed of stiff insulating material and fitted closely over a -ferrule which joins the detonator to the swaged rear end portion of the sleeve 25. On the rear face oi the ring 36 are mounted two copper leaf springs 31 and 38 so positioned that they are normally out of contact with each other. When the piston 2| slides the detonator home into the booster recess I5, the outer leaf 38 of the switch engages the end of the booster and is forced against the inner leaf 31 to close switch 35.

Even after the sea cell 30 has become activated and the switch 35 has been closed, the detonator will not be red until a second switch 4|) is closed. The switch 40 is a mercury jiggle switch comprising a ring-shaped member 4I (Fig. 3)

having a terminal connected to a lead 42, and an elongated contact 43 having a terminal connected to a lead 44. A small quantity of mercury 45 is included within a glass container 45a with the contact 43 and the ring 4|, and as the switch is jiggled the mercury splashes and momentarily establishes an electrical circuit between the leads 42 and 44. It will be apparent that when the sea cell 30 becomes activated and the switches 35 and 4|!l are both closed, the detonator 21 will re so as to set oi the booster I4 and ignite the main explosive charge.

`In the unarmed condition of the fuze, its parts are in the position shown in Fig. 2 and are retained in that position by a, coil spring 50 in the housing Ill, the spring 5I] bearing at one end against the booster and at the other end against the rear flange 22 of the subassembly. To prevent the subassembly 20 from jarring in the tube l notwithstanding the spring 50, a cap nut 5| is threaded on a shank 53 secured in and projecting Vfrom the nose end of the sea cell 30 which engages an internal shoulder 54 on the nose end of the subassembly. The nut is seated in an opening in the nose cap |5a and is tightened so as to draw the subassembly against the nose cap.

The initial step in arming the fuze is to pull out the nut 5I and with it the threaded shank 53 from the sea cell. This permits access of water into the cell to activate it when the projectile enters the Water. As the projectile enters the water, the sea cell quickly begins to function as a battery and is a potential source of current for the fuze detonating circuit shown in Fig. 4. It has been found that by initially connecting a resistance 55 (Fig. 4), comparable to the load resistance, across the sea cell, a relatively high current through the load resistance is obtainable from the cell and the activation of the cell is materially speeded up.

The sea water under pressure enters the sleeve I0 through the opening in nose cap I5, and builds up pressure in front of the packing 23, thereby forcing the entire subassembly to the rear (Fig. 2) against the action of spring 5l). Thus, the detonator is moved into the booster recess VI5 and the contacts of switch 35 are closed, as previously described, so that a complete electrical circuit is established between the sea cell and the detonator except for the fact thatthe jiggle switch 40 remains open.

When the projectile moving through the water contacts a target, it receives a shock or impact suiiicient to close the contacts of switch 40 momentarily due to splashing of the mercury 45, thereby allowing passage of the necessary current to the detonator to re it.

It will be seen that the new fuze includes several features for rendering it safe in handling. In the unarmed position of the fuze, the detonator is far enough from the booster to prevent premature operation of the detonator from affecting the booster. Furthermore, the source of electrical energy is completely inactive before the projectile enters the water, and the circuit from the cell to the detonator is open by reason of the switches 35 and 40. The fuze arms quickly on submersion in water and fires, after arming, if the projectile undergoes a slight jarring action. Since the piston 2| carries the detonator and the operating means for the detonator, the fuze may be readily assembled. The piston serves the dual function of moving switch 35 and detonator 21 to their armed positions and housing the battery, the

- position.

2. In a fuze having a housing provided with an opening, a sub-assembly in the housing comprising a piston movable from a safe to an armed position by pressure uid entering through said opening, a battery carried by the piston, an electrical detonator carried by the piston, a normally safe switch carried by the piston in circuit with the battery and the detonator and movable to an armed position upon movement of the piston to its armed position, and a shock-responsive switch carried by the piston in circuit with the detonator and the battery.

3. In a fuze having a housing provided with an opening, a sub-assembly in the housing comprising a piston movable from a safe to an armed position by pressure fluid entering through said opening, a seat battery carried by the piston at one end thereof, an electrical detonator carried by the piston at the opposite end thereof, and means carried by the piston including a normally safe switch for connecting the detinator in circuit with the battery when the piston is moved to its armed position.

.4. In a fuze having a housing provided with an opening, a sub-assembly in the housing comprising a piston movable from a safe to an armed position by pressure iiuid entering through said opening, a battery mounted in the piston, an electrical detonator carried by the piston, and a shock-responsive switch mounted in the piston for connecting the detonator in circuit with the battery.

5. A fuze comprising a housing having an opening, a booster in the housing, a detonator normally disposed in a safe position with respect to the booster, a piston in the housing operable by pressure fluid entering through said opening to move the detonator to an armed position with respect to the booster, a normally inactive sea battery carried by the piston and adapted to be activated by said pressure fluid, and a normally safe switch carried by the piston and movable to an armed position by operation of the piston for connecting the battery in circuit with the detonator.

6. In combination, a sea-activated battery, a detonator and a switch connected in series circuit, and an initial load resistance connected across the sea battery and comparable to the load resistance of the detonator, whereby the battery is adapted to build up to capacity quickly prior to closing of the switch.

7. A fuze comprising a. housing having an opening, a booster in the housing, a detonator normally disposed in a safe position with respect to the booster, a piston in the housing operable by pressure iiuid entering through said opening to move the detonator to an armed position with respect to the booster, a normally inactive sea battery carried by the piston and adapted to be activated by said pressure iiuid, a normally safe switch carried by the piston and movable to an armed position by operation of the piston for connecting the battery in circuit with the detonator. and releasable means in said opening for blocmng the opening and locking the piston against operation.

GEORGE E. BREEZE. GODWIN R. F. GAY.

REFERENCES CITED The following references are of record in the le of this patent:

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